RT Journal Article SR Electronic T1 Rationality Was Lost on the United States Supreme Court in Its Kahler Decision JF Journal of the American Academy of Psychiatry and the Law Online JO J Am Acad Psychiatry Law FD American Academy of Psychiatry and the Law SP JAAPL.210054-21 DO 10.29158/JAAPL.210054-21 A1 Alan R. Felthous YR 2021 UL http://jaapl.org/content/early/2021/12/21/JAAPL.210054-21.abstract AB In its recent Kahler decision, the U.S. Supreme Court ruled that Kansas’ abolition of the state’s insanity defense was constitutional. It did so by framing the matter as a choice between the state’s mens rea defense and a moral capacity defense, then mischaracterizing the mens rea defense as a type of insanity defense. In analyzing the two approaches, the Court missed the fundamental importance of rationality in criminal mental responsibility, a constitutional requirement for other criminal competencies, and a condition well described in the Court’s Panetti ruling. The Court’s acceptance of the abolition of a special insanity defense is a public policy in the direction of further criminalizing and punishing rather than providing prompt and proper treatment to those with serious mental illness, at a time when increasing modern research demonstrates the success of insanity acquittee dispositions with improved treatment and management resulting in lower rates of relapse and criminal recidivism.